BEIJING, April 2 (Xinhua) -- China's police will start a three-month campaign till the end of June this year to eliminate unnatural deaths of inmates in prisons and detention centers, according to the Ministry of Public Security.

Police authorities across the country must learn from the recent death of Li Qiaoming in the southwestern province of Yunnan, and make sure such an incident not to happen again, the ministry said at its website Tuesday.

Li, 24, was beaten to death by three other inmates at a detention center in the Jinning county, southwest China's Yunnan Province, in February. Detention officers at first claimed Li died of an accident when playing hide-and-seek with other inmates.

The ministry urged local authorities to strengthen education among police officers at prisons and detention centers in the three-month campaign to boost professional ethics, law awareness and respect for human rights.

"Officials should be brave to reveal their problems in the management of prisons and detention centers, and should exert doubled efforts to address them," the ministry said.

Inspections and investigations will be carried out after the campaign to determine if problems have been corrected, it said.

China saw at least four more cases of custody deaths in the past month. They included two minors who reportedly died over four days at a provincial juvenile reformatory in Hunan Province, a 19-year-old Xu Gengrong who died on March 8, the seventh day of his detention in Shaanxi Province, and 50-year-old Li Wenyan, who allegedly died in the middle of a "nightmare", according to the head of a detention department in Jiujiang of the eastern Jiangxi Province.